Usually, an ink-jet recording device repeatedly moves a recording head, with a plurality of ink-ejecting nozzles arranged thereon, in the direction different from the nozzle arrangement direction to form a band of image area (band) during one movement. This repeated one-band image recording, one band for each specific amount of movement of recording medium, completes one whole image recording.
Today, there are a variety of recording media for use in the ink-jet recording device. Among these recording media, print results look much more beautiful on lustrous paper or film than on plain paper. Furthermore, the ink-jet recording device may print on cloth such as cotton or enamel. This demand will grow in future.
However, some of these media described above do not absorb ink well, and some others are easily blurred. Printing on these recording media results in an overflow of ink in a high-density print area, significantly degrading the print image quality. This degradation depends on the characteristics of the recording media. The overflow of ink also dirties some mechanical parts of the ink-jet recording device, such as a platen, sometimes affecting print operations.
The conventional solution to this problem is that the ink ejection amount is limited by a masking that is performed during the preprocessing of conversion from gray-scale images to binary (bi-level) images.
However, the prior art described above has the drawbacks described below because the correction is made on an image signal basis.
First, a popular ink-jet recording device is connected, in most cases, to a computer terminal. This computer terminal performs image processing, such as conversion to binary values, and transfers the processed result to the ink-jet recording device for recording thereon. However, an image input unit or an image processing unit which processes multi-valued signals, if built in an ink-jet recording device, would increase the cost and the processing time and, therefore, they are not standard on a popular ink-jet recording device. When an ink-jet recording device performs correction on an image signal basis, conversion from gray-scale images to binary images waists time and the recording speed is reduced. An ink-jet recording device according to the present invention makes correction, not on multi-valued signal, but on binary image data.
It is therefore an object of the present invention to prevent image quality degradation caused by a blur on the recording medium by limiting, through binary image processing, the ink ejection amount to a level at which no image degradation is caused by a blur on the recording medium.
It is another object of the present invention to reduce the change in color and to produce a good-quality color image recording even when the ink ejection amount is limited during color image recording.